Such a conference system is already known in the art e.g., from the published European patent application 153 903 B1. In this known conference system which is a video conference system, image stores and image production controls constitute the above mentioned conference control unit while the mentioned switching unit includes a set of multiplexers. The image stores and production controls as well as the multiplexers are incorporated in a video conference center to which subscribers located at different sites are connected. Groups of image stores and multiplexers are interconnected for the purpose of a conference and the image controls control the storage and reproduction of the images received from/to the different sites participating in the video conference. The thus realised video conference center has to perform switching functions, i.e. interconnection of the above mentioned groups and set up of connections to the different sites involved in a conference, as well as conference control functions. Moreover both functions are linked: to perform the switching functions, the video conference center has to know about the agreed conference parameters. This means that the conference control part of the video conference center can only interwork with a dedicated switching part.